Purging system for refrigeration systems



March 151949.. J. R, zwlcKL 2,464,631

PURGING SYSTEM FOR REFRIGERATION SYSTEMS Filedflov. 9. 1946 IN V EN TOR.

Patented Mar. 15,1949- PURGING SYSTEM FOR SYSTEMS ZwickLDrange, N. .L, assignor to I Joseph R.

REFRIGERATION Worthington Pump and Machinery Corporation, Harrison, N. 1., a corporation of Delaware Application Novemberil, 1946, Serial No. 708,840 9 Claims. (Cl. 52-115) This invention relates to purging systems for refrigeration plants and more particularly to means for removing impurities, such as oil, which are soluble in the refrigerant.

While the present invention may be used in various purge systems, it is particularly adapted to improve the operation of the system disclosed in the inventors prior Patent Ito-2,400,620, issued May 21, 1946. This patent discloses a purge circult in which the gases are led from the foul gas header of the main condenser to a purge compressor, from the compressor through an oil collector or separator to a condenser, and from the condenser to a separator drum wherein the refrigerant, water, and non-condensible gases are separated. Effective separation of the oil is not always obtained in this circuit, however, due to the fact that the gases leaving the compressor are at such a pressure that they are prone to condense or liquify before leaving the oil collector. The condensate which collectsin the oil collector may be discharged back into the crankcase of the compressor where it varporizes and otherwise interferes with the operation of the compressor.

It is the object of the present invention to eliminate this undesirable feature and to provide means for effectively withdrawing the oil, or other soluble impurities, from the refrigerant. This is accomplished by vaporizing the refrigerant received from the separator drum and passing the 4 mixture of gas and liquid oil into a trap or collector wherein the oil is collected while the refrigerant vapor passes through to be guided back to the main refrigeration system. The collector contains a coil through which the hot compressed gases pass after leaving the compressor. This heats the oil in the separator and prevents re-absorption of the refrigerant. The evaporator is positioned adjacent to the condenser so that the heat released in the condensing stage may be utilized in the evaporation stage.

With these and other objects in view, as may appear from the accompanying specification, the

invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawing, showing a purging system for refrigeraton plants of a preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

The drawing is a schematic diagram of a purge system embodying the improved means for removing soluble impurities from the refrigerant.

Refrigerant vapor containing impurities is drawn from the condenser (not shown) of the main refrigeration plant through the inlet lineactuated switch structure ll of approved construction which is connected to the compressor motor (not shown) and to the inlet and outlet lines i and 6 so that the compressor will operate only within predetermined limits of pressure in the lines I and 6.

, The refrigerant vapor and condensible impurities such as water vapor are substantially all condensed in the condenser 8 and the condensate together with the non-condensibles passes through the line [2 into the lower portion of the purge or separator drum l3 The lower portion of the drum l3 contains a separator structure It, fully described in the previously mentioned Patent No. 2,400,620, which utilizes the difference in densities to separate the liquid refrigerant from the condensed impurities, such as water. The water is collected in the inner chamber l5 having an outlet l6 and the liquid refrigerant is collected in the outer annular chamber I'l having an outlet line l8. The non-condensible gases entering the drum l3 with the liquid constituents rise and fill the remaining portion of thedrum and carry with them a certain amount of non-condensed refrigerant and water vapor. These gases contact the strip condenser [9 within the drum l3 and are effectively stripped of the refrigerant and water which condense and fall into the separator structure [4 where they are collected in chambers I5 and IT.

The upper portion of the drum [3 has an outlet line 20 in which are placed a solenoid operated valve 2|, a needle valve 22, and an orifice 23. The solenoid valve 2| is operated by a suitable pressure switch 24 to control the releaseof noncondensible gases and to maintain the pressure in the drum l3 within predetermined limits. Normally, the orifice 23 prevents rapid escape of gases from the drum and therefore increases the duration of the strip condensing stage, but rapid venting may be obtained by opening the needle valve 22, which is placed between the orifice 23 and the solenoid valve 2|.

The separated refrigerant collected in chamber I1 is used as a cooling medium for the strip condenser IS. A float valve structure 25, of suitable construction, is connected to a solenoid operated valve 28 in the line l8 to control discharge of liquid refrigerant-from chamber H in accordance with its level therein. The outlet line I! also has an expansion needle valve 21 which controls the flow of the expanded cold refrigerant through the strip condenser l9.

The separated refrigerant leaving the strip condenser I! by means of pipe 28 is substantially all liquid because of the small quantity of heat released by the constituents not condensed in condenser 8 and may contain'soluble impurities such as oil which may have been Picked up in the purge compressor 2. To separate the oil fromthe re frigerant the line 28 carries them to a suitable evaporator 29 wherein the refrigerant is vaporized while the oil, or other impurity less volatile than the refrigerant, remains liquid. The mixture of refrigerant vapor and oil passes through the pipe 30 and is discharged into a suitable trap or collector Ill, which may be purchased on the open market, wherein the oil settles to the bottom. The vapor rises through the Raschig rings, or tortuous baflle means, which removes any remaining traces of liquid particles and flows back to the main refrigeration system through the outlet line 32, constant back pressure valve 33, and manually operated valve 34.

The oil collected in the separator l may be returned to the crankcase of the compressor 2 through the line 35. The passage therethrough may be controlled by suitable means such as a needle valve 36 or a float valve structure (not shown). As previously mentioned the oil in the collector I 0 is heated by means of the compressed gases passing through the coil 9 therein, though other heating means could be employed to the end evaporator may be used in the pur e system, it

has been found to be particularly efllcient to use an air-blast condenser-evaporator as schematically illustrated in the drawing. In this structure the condenser 8 is cooled with air driven by the fan 31 which may be connected to the compressor motor. The air which is heated by contact with the condenser is then passed over the evaporator 29 and supplies the heat for vaporizing the refrigerant passing through its coils.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention defined by the claims.

What is claimed is:

1. In a purging system for removing impurities from a volatile refrigerant of a refrigeration plant, means for removing impurities soluble in but less volatile than the refrigerant including an evaporator for vaporizing the refrigerant, a collector connected to said evaporator for collecting and separating impurities from the vaporized refrigerant, and means connected to said collector for returning the refrigerant vapor tothe main refrigeration system, said last mentioned means including tortuous baille means to prevent the passage therethrough of liquid particles.

2. In a refrigeration plant employing a volatile refrigerant and having a purge system containing a compressor, a condenser, means for separating the condensibles and non-condensibles from the refrigerant, and connections for the flow of therefrigerant and impurities from the compressor to the condenser to the means; the means for removing oil from the refrigerant including an evaporator for vaporizing the refrigerant, means for delivering the separated refrigerant to said evaporator, a collector connected to said evaporator wherein the oil is separated from the vaporized refrigerant, means for heating the oil collected in said collector, saidmeans comprising a coil immersed in the oil and having an inlet and outlet inserted in the connection between the compressor and the condenser whereby the compressed gases flow through said coil, means connected to said collector for returning the refrigerant vapor to the main refrigeration system, and means for delivering the oil collected in said collector to the crankcase of the compressor.

3. In a refrigeration plant employing a volatile refrigerant and having a purge system containing a compressor, a condenser, means for separating the condensibles and noncondensibles from the refrigerant, and connections for the flow of the refrigerant and impurities from the compressor to the condenser to the means; the means for removing oil from the refrigerant including an evaporator for vaporizing the refrigerant, a connection between said evaporator and the separating means for delivering separated refrigerant and impurities dissolved therein to said evaporator, a collector connected to said evaporator for collecting and separating the oil from the vaporized refrigerant, means for heating the oil collected in said collector, means connected to said collector for returning the refrigerant to the main refrigeration system, and means for delivering the oil collected in said collector to the crankcase of the compressor.

4. In a refrigeration plant employing a volatile refrigerant and having a purge system which includes a compressor, an air-blast condenser, means for separating the condensibles and noncondensibles from the refrigerant, and connections for delivering refrigerant and impurities from the compressor to the condenser and from the condenser to the separating means; the means for removing oil from refrigerant including an evaporator for vaporizing the refrigerant, means for delivering the separated refrigerant from the separating means to the evaporator, a collector connected to said evaporator for separating and collecting the oil from the vaporized refrigerant, said evaporator being positioned adjacent to the air blast condenser whereby the heat removed from the constituents flowing through said condenser will be utilized to vaporize refrigerant flowing through the evaporator, and means connected to said collector for returning the refrigerant vapor to the main refrigeration system.

5. In a refrigeration plant employing a volatile refrigerant and having a purge system which includes a compressor, an air-blast condenser, means for separating the condensibles and noncondensibles from the refrigerant, and connections for delivering refrigerant and impurities from the compressor to the condenser and from the condenser to the separating means; the means for removing oil from the refrigerant which comprises an evaporator for vaporizing the refrigerant, said evaporator being positioned adjacent to the air-blast condenser whereby the heat removed from the constituents flowing through said condenser will be utilized to vaporize refrigerant flowing through the evaporator, a, connection between said evaporator and the separating means for delivering separated refrigerant and impurities dissolved therein to said evaporator, a collector connected to said evaporator for collecting and separating the oil from the vaporized refrigerant, means for heatin the oil collected in said collector, said means comprising a coil immersed in the oil and having its inlet and outlet in the connection between the compressor and the condenser whereby the compressed gases flow through said coil, means connected to said collector for returning the refrigerant vapor to the main refrigeration system, said means including tortuous bafiie means to prevent the passage therethrough of liquid particles, and means for delivering the oil collected in said collector to the crankcase of the compressor.

6. In a refrigeration plant employing a volatile refrigerant and having a purge system containing a compressor, a condenser, means for separating the condensibles and non-condensibles from the refrigerant, and connections for theflow of the refrigerant and impurities from the compressor to the condenser; means for removing oil from the refrigerant including an evaporator for vaporizing the refrigerant, means for delivering the separated refrigerant to said evaporator, a collector connected to said evaporator wherein the oil is separated from the vaporized refrigerant, means for heating the ofl collected in said collector, said means comprising a coil immersed in the oil and having an inlet and outlet inserted in the connection between the compressor and the condenser whereby the compressed gases flow through said coil.

'1. In a purging system for removing impurities from a volatile refrigerant in a refrigeration plant, means for removing impurities soluble in but less volatile than the refrigerant including an evaporator for vaporizing the refrigerant, a colto said evaporator for collecting and separating impurities from the vaporized refrigerant, a conduit-in said collector having its inlet connected to the discharge of the compressor for conducting heated compressed refrigerant through the collector, means for returning refrigerant flowing through said conduit to said collector in isolated separation from the refrigerant flowing through the conduit whereby the refrigerant flowing through the conduit will heat the returning refrigerant to advance separation of refrigerant and soluble less volatile impurities, said collector having an outlet for the refrigerant and a separate outlet for ,the impurities,

9. In a purging system for removing impurities from a volatile refrigerant of a refrigeration ,plant, means for removing impurities soluble in but less volatile than the refrigerant including a purge compressor for receiving refrigerant from the main refrigerating system, an evaporator for vaporizing the refrigerant, a collector connected to said evaporator for collecting and separating impurities from the vaporized refrigerant, a conduit in said collector having its inlet connected to the discharge of the compressor for conducting heated compressed refrigerant through the collector, means for returningrefrigerant flowing through said conduit to said collector in isolated separation from the refrigerant flowing through the conduit whereby the refrigerant flowing through the conduit will heat the returning refrigerant to advance separation of refrigerant and soluble less volatile impurities, said collector having an outlet for the refrigerant and a separate outlet for the impurities, and tortuous baflie means in said collector adjacent to the refrigerant outlet to prevent the passage of liquid lector connected to said evaporator for collecting and separating impurities from the vaporized refrigerant, means in said collector for heating the vaporized refrigerant and soluble less volatile impurities to advance separation thereof, and:

independent outlets from said collector for the vaporized refrigerant and impurities.

8. In a purging system for removing impurities from a volatile refrigerant of a refrigeration plant, means'for removing impurities soluble in particles therethrough.

JOSEPH R. ZWICKL.

' REFERENCES crrm The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 

